Frame construction for filter units



1959 R. J. BRECKHEIMER FRAME CONSTRUCTION FOR FILTER UNITS Filed June 19, 1957 INVENTOR RAYMOND J. BRECKHEIMER ATTORNEYS United States FRAME CONSTRUCTION FOR FILTER UNITS Raymond. J. Breckheirner, Milwaukee, Wis., assignor to Air Filter Corporation, Milwaukee, Wis, a corporation of Milwaukee Application June 19, 19,57, SerialNo. 666,612.

3 Claims. (Cl. 189-66) Another salient object of my invention is to provide a frame for air and like filters formed from a single a strip of material of a U-shape in cross-section bent into a rectangle or desired shape to form top, bottom and end rails with a novel means for rigidly uniting the ends of the strip together at a corner of the frame to complete the assembly.

A further object of my invention is to provide the ends of the strip with terminal tongues for novel connection with adjacent parts of the strip, so that the tongues will brace and add rigidity to the frame and at the same time form a secure, firm connection, which will resist strains in all directions so that inadvertent opening of the joint will be eliminated.

A still further important object of my invention is t the provision of a long brace tongue on one end of the strip for insertion in keeper slots in an adjacent rail of the frame and a short lock tongue on the other end of the strip adapted to be bent completely back on itself through an opening in the first rail against said rail whereby displacement of the long brace tongue and the opening of the connection will be prevented.

With these and other objects in view, the invention consists in the novel construction, arrangement and formation of parts as will be hereinafter more specifically described and claimed and illustrated in the accompany- ,ing drawing, in which drawing,

Figure 1 is a perspective view of a filter embodying my novel frame;

Figure 2 is an enlarged detail sectional view taken on the line 22 of Figure 1, looking in the direction of the arrows, showing my improved joint or connection for the ends of the frame strip;

Figure 3 is an exploded view of one corner of the frame prior to the joining of the adjacent rails together by my novel lock or connection;

Figure 4 is a view similar to Figure 3, but showing the long tongue inserted through the keeper slots in an adjacent rail;

Figure 5 is a view similar to Figure 4, but showing t the short tongue bent back upon itself and in its locked position for completing the joint, and

Figure 6 is a detail transverse sectional view taken on the line 66 of Figure 2, looking in the direction of the arrows, the view showing more particularly the throughout the several views, the letter F generally indi- 2,869,694 Patented Jan. 26), 1959 'ice single strip of sheet metal or other desired material, and

this strip in its bent form is of a U-shape in cross-section. The strip is bent to form top and bottom rails 12 and 13, and end rails 14 and 15. As heretofore brought out in the objects of theispecification, the invention relates specifically to the novel connection of the terminals of the strip. or the joining of theterminals of adjacent rails to keep the formation of a rugged frame. Thus, one rail 12 has its forward edge bent downwardly at right angles to provide an abutment flange 16 and this flange is continued to form a long brace tongue 17.. The outer wall of the rail 12 adjacent to the flange 16 is provided with an opening 18, the purpose of which will later appear.

The rail 14 has formed on its upper end a short lock tongue 19. The outer wall of the rail 14 inward of the tongue 19 is provided with spaced parallel transverse slots 20, and the material of the strip between the slots 20 is struck inwardly to form a guide loop 21.

After the bending of the elongated strip to form the rails, the terminals of the rails 12 and 14 are brought toward one another and the long brace tongue 17 is inserted through the slots 20 as best shown in Figures 2 and 4. The struck in loop 21 receives and braces the tongue 17. After the insertion of the long brace tongue 17 in its slots 20, as shown in Figure 4, the short lock tongue 19 is then bent back onitself through the opening 18 in firm contact with the inner face of the outer wall of the rail 14 (see Figures 2 and 5). The bending back of the lock tongue 19 prevents the pulling apart of the rails 12 and 14 and the bending of the tongue 19 into firm contact with the rail 14 prevents the withdrawal of the long tongue 17 from the slots 20. The tongue 17 and its carrying fiange 16 forms a rigid brace structure which prevents the forcing of the rail 14 inwardly and thus prevents the distortion of the frame.

Great stress is laid on the complete bending back of the short lock tongue 19, for the reason that, in some structures holding tongues are bent at right angles and these right angular tongues tend to spring back to their normal position which allows loosening of the frame.

If preferred the long tongue 17 can be provided with one or more struck out ratchet teeth 22 and when the long tongue 17 is inserted through the slots 29 the ratchet tooth 22 will spring out and engage the upper wall of the topmost slot and this aids in preventing the withdrawal of the tongue 17 from the slots.

The opening 18 has another advantage, in that, when the filter F is washed, the opening 18 will constitute a drain to permit the free flow of cleaning fluid from the frame and the filtering screens.

Various other changes in details may be made without departing from the spirit or the scope of this invention, but what I claim as new is:

l. A filtering unit comprising a marginal frame including top, bottom and side rails and means for securing the terminals of adjacent rails in rigid locked engagement including an elongated brace tongue carried by one rail and extending at right angles thereto, the other adjacent rail being provided with spaced transversely extending slits for receiving said brace tongue, said tongue being in facial contact with the last mentioned rail, and a short lock tongue on said last mentioned rail, and said first mentioned rail having an opening adjacent. to the base of the elongated brace tongue for the reception of the short lock tongue when the elongated brace tongue is in said slits, said short tongue being bent back upon itself through the opening into facial contact with said first rail.

.2 An air filtering unit comprising a marginal frame as defined in claim 1 and said elongated brace tongue having a struck out ratchet tooth engaging the upper wall of one slit when said elongated brace tongue is fully inserted in said slits. I

3. An air filtering unitcomprising a marginal frame including top, bottom and side rails and means for rigidly uniting adjacent ends of rails togetherjncluding a right angularly extending flange formed on the end of one rail,

a long brace tongue forming a continuation'of theflange and in the same plane therewith, said railhaving an opening adjacent to the base of the flange, a short lock tongue on the end of the other adjacent rail, said last mentioned rail having spaced transversely extending slits and a de pressed portion between the slits, said brace tongue being in facial engagement with the inner face of the last mentioned rail, and said short lock tongue being bent back upon itself through the opening adjacent the flange and in facial gripping contact with the flange, whereby to hold the flange tight against the last mentioned rail and to prevent the pulling apart of said adjacent rail ends.

References Cited in the file of this patent UNITED STATES PATENTS 1,975,622 Schermerhorn Oct. 2, 1934 2,023,604 Lovejoy Dec. 10, 1935 2,627,948 Farr Feb. 10, 1953 2,723,731 t Schaaf Nov. 15, 1955 

